The present invention relates generally to hitches for attaching towed implements to agricultural tractors and more particularly to an apparatus for reducing lateral impact loading on a tractor drawbar caused by implements being towed.
Agricultural tractors are often used to pull implements, such as wagons and carts, by connection to the tractor's drawbar. Drawbars are typically connected to a tractor using a pivotal connection that allows the hitch end of the drawbar to move through an arc. Movement of the drawbar simplifies coupling of an implement by eliminating the need to precisely align the tractor and implement relative to each other during coupling operations and thus simplifying the coupling operation. While such movement benefits the implement coupling operation, excessive movement in the drawbar connection during implement towing can lead to unintentional implement movement and even amplify trailer surge or sway movements. Controlling drawbar movement after coupling an implement has led to numerous devices for rigidly fixing the drawbar into position thereby preventing unwanted lateral movement of the drawbar.
During movement of the tractor and coupled implement, the drawbar may be subjected to impact loads in various directions. Side loading is particularly noticeable while pulling single-axle trailers, such as a grain carts. When only one wheel of a single-axle trailer contacts an obstruction the resulting force creates a moment about the center of the implement axle that is transferred as a lateral impact load to the tractor through the drawbar. Impact loads on the tractor drawbar require additional materials in the drawbar attachment structure to withstand the higher stresses and can cause discomfort to the tractor operator.
It would be a great advantage to provide a simple device to incorporate side cushions in the drawbar connection to the tractor to attenuate the lateral impact loads on the tractor. These and other advantages are provided by the draft control system described below.